9654 device weight (#10448)

* 9654 add weight fields to devices

* 9654 changes from code review

* 9654 change _abs_weight to grams

* Resolve migrations conflict

* 9654 code-review changes

* 9654 total weight on devices

* Misc cleanup

Co-authored-by: Jeremy Stretch <jstretch@ns1.com>

netbox/dcim/choices.py

@@ -1314,6 +1314,24 @@ class CableLengthUnitChoices(ChoiceSet):
     )
 
 
+class WeightUnitChoices(ChoiceSet):
+
+    # Metric
+    UNIT_KILOGRAM = 'kg'
+    UNIT_GRAM = 'g'
+
+    # Imperial
+    UNIT_POUND = 'lb'
+    UNIT_OUNCE = 'oz'
+
+    CHOICES = (
+        (UNIT_KILOGRAM, 'Kilograms'),
+        (UNIT_GRAM, 'Grams'),
+        (UNIT_POUND, 'Pounds'),
+        (UNIT_OUNCE, 'Ounces'),
+    )
+
+
 #
 # CableTerminations
 #